As methods for creating a high-class appearance in the interior panels of automobiles, the panels of audio equipment, the box portions of music boxes, the panel portions of furniture, and the like; there are known methods of finishing these portions in the front surfaces of wood patterns. Examples of methods for doing so include methods of bonding/fixing an ornamental sheet to the front surface of a substrate by using a vacuum press bonding method. Patent Documents 1 to 4 propose methods for bonding/fixing an ornamental sheet to the front surface of a substrate by using a vacuum press bonding method.
In the vacuum press bonding method disclosed in Patent Document 1, a workpiece comprising an ornamental sheet placed on the front surface of a substrate via an adhesive is placed on a workpiece mounting surface formed on the top surface of a suction chamber, a pressure chamber is lowered from above, and the ornamental sheet is pressed onto the substrate front surface by a flexible pressure sheet constituting the bottom surface of the pressure chamber. In this state, the pressure of the pressure chamber is increased to firmly pressure-bond the pressure sheet to the ornamental sheet and the workpiece mounting surface, and the pressure of the suction chamber is reduced to evacuate the space between the pressure sheet and the workpiece mounting surface via a suction hole formed in the workpiece mounting surface. The ornamental sheet thereby becomes pressed against the substrate surface with the pressure sheet firmly bonded to the ornamental sheet, and the ornamental sheet is bonded/fixed to the substrate surface by an adhesive.
In the vacuum press bonding methods disclosed in Patent Documents 2 to 4, a base for mounting a substrate is placed on the top surface of a suction chamber where a suction hole is formed, and a substrate and ornamental sheet are placed on the base. This makes it possible for the pressure sheet of the pressure chamber to be firmly bonded to a workpiece, encompassing a portion from the outer periphery to the rear surface, and the outer peripheral edge portion of the ornamental sheet can be reliably bonded/fixed to the substrate, encompassing a portion from the outer peripheral edge to the back surface.